Shoe with ventilation system

ABSTRACT

A shoe comprising upper, bottom fixed to the upper, ventilation system and insole disposed above the bottom and obtained by injection molding of polyurethane foam. The ventilation system is integrated inside the insole in such a way not to interfere with the bottom and with an outsole that must be applied under the bottom.

The present application for industrial invention relates to a shoe withventilation or transpiration system, and in particular to anaccident-prevention shoe.

As it is known, a shoe is mainly made of an upper that wraps the footaround and an outsole that is glued to the upper and acts as tread. Intraditional shoes the two parts are manufactured separately and thenglued. Therefore, before gluing the outsole on the upper, variousmechanisms can be inserted in the outsole to obtain a transpirationsystem. Transpiration systems applied to this type of shoe are availableon the market.

In some shoes an bottom is joined to the upper and then the outsole isglued or injection-molded under the bottom. In such a case, it is ratherdifficult to provide for ventilation systems integrated into theoutsole, unless the bottom is suitably modified.

U.S. Pat. No. 5,826,349 and US2005/0005473 disclose shoes withventilation system integrated in the outsole and in the bottom of theshoe.

Such an inconvenience is especially experienced in accident-preventionshoes that require a continuous metal plate in the outsole or a Kevlarsheet in the bottom. It appears evident that in such cases theventilation mechanism interferes with the metal plate or Kevlar sheet.

To solve these inconveniences, at least partially, solutions are knownthat provide for realizing a ventilation mechanism in the insoledisposed above the bottom of the shoe.

US2008/0313930, U.S. Pat. No. 5,996,250, U.S. Pat. No. 3,180,039, andDE20119030 disclose an insole provided with ventilation mechanism.

However, the insoles of the prior art are only realized by coupling twosheets in order to contain the ventilation mechanism. Consequently, thestructure of the insole is uncomfortable for the user. Moreover, such atype of insole structure cannot be molded with a suitable soft material,such as polyurethane foam.

The purpose of the present invention is to eliminate the drawbacks ofthe prior art, disclosing a method for production of a insole withventilation system that is comfortable for the user.

Another purpose of the present invention is to provide a insole withventilation system that can be easily combined with a shoe withoutinterfering with the bottom or the outsole of the shoe.

These purposes are achieved by the present invention according to thefeatures claimed in the enclosed independent claims.

Advantageous embodiments are disclosed in the dependent claims.

The insole of the invention comprises a lower layer of polyurethane foamobtained with injection molding and disposed under a ventilation system,with borders folded in such a way to surround the peripheral borders ofsaid ventilation system.

The advantages of the shoe comprising the insole of the invention areevident, since it provides for ventilation of the user's foot and hasbeen studied in such a way that the ventilation system does notinterfere with the bottom or outsole of the shoe and is at the same timecomfortable for the user.

Additional characteristics of the invention will become more evidentafter a detailed description that refers to a merely illustrative, notlimiting, embodiment, as shown in the enclosed figures, wherein:

FIG. 1 is an exploded top view that shows the various parts of theventilation system of the shoe of the invention;

FIG. 2 is a top view of a leather sheet that is part of the ventilationsystem;

FIG. 3 is a bottom view of the ventilation system complete andassembled;

FIG. 4 is a cross-sectional view of the ventilation system assembled;

FIG. 5 is a diagrammatic cross-sectional view of a mold for injection ofpolyurethane foam for realization of the insole for shoe of theinvention;

FIG. 5 A is an enlarged view of the detail contained in the circle A ofFIG. 5;

FIG. 6 is a cross-sectional view of the semi-finished insole obtainedwith the mold of FIG. 5;

FIG. 7 is a cross-sectional view of the finished insole after cuttingthe leather sheet; and

FIG. 8 is a cross-sectional view of a shoe with the insole of FIG. 7.

Now referring to FIGS. 1-4 a ventilation system according to theinvention is disclosed, which is generally indicated with numeral (2).

The ventilation system (2) comprises a lower sheet (3) of softdeformable material, such as soft thermoplastic polyurethane (TPU) withShore A hardness lower than 65. The lower sheet (3) has a flattenedshape, basically similar to the front of the foot.

The lower sheet (3) comprises deformable spacers (31) that protrudeupwards. As shown in FIG. 4, the spacers (31) are shaped as internallyempty rectangular projections. This means that the lower side of thesheet (3) is provided with a plurality of recessed seats (34) incorrespondence with the spacers (31).

A plurality of air spaces (32), which are shaped as communicatingchannels, is generated between the spacers (31). The air spaces (32) arein communication with an outlet channel (33) at the back end of thelower sheet (3). A connection pipe (20) is coupled in the outlet channel(33).

A pump (4) comprises a lower semibody (41) and an upper semibody (42)that are coupled to form a pumping chamber (40) (see FIG. 4) whichcommunicates with the air spaces (32) of the lower sheet (3) by means ofthe connection pipe (20).

The lower semibody (41) is made of hard rigid plastic material, such ashard thermoplastic polyurethane (TPU) with Shore A hardness higher than95. Instead, the upper semibody (42) is made of soft flexible plasticmaterial, such as soft thermoplastic polyurethane (TPU) with Shore Ahardness lower than 65. The two semibodies (41, 42) are coupled by heatsealing or gluing the peripheral portions.

The chamber (40) of the pump communicates with the air outlet pipe (21)that extends in the back to be brought out of the shoe.

A valve unit (7) is coupled in the front part of the pump (4). Referringto FIG. 1, the valve unit (7) comprises a rectangular block (70) made ofrigid plastic material, which is provided with:

a U-shaped conduit (71) with inlet in communication with the chamber(40) of the pump and outlet in communication with the outlet pipe (21);anda longitudinal conduit (72) with inlet in communication with theconnection pipe (20) and outlet in communication with the chamber (40)of the pump.

The valve unit (7) can be made in one piece with the lower semibody (41)of the pump.

A first non-return (one-way) valve (5) is installed at the inlet of theU-shaped conduit (71). The first non-return valve (5) permits air flowfrom the chamber (40) of the pump to the air outlet pipe (21) and notvice versa.

For illustrative purposes, the first non-return valve (5) comprises aspherical shutter (50) with a spring (51) to maintain the valve normallyclosed.

A second non-return (one-way) valve (6) is installed in the longitudinalconduit (72). The second non-return valve (6) permits air flow from theconnection pipe (20) to the chamber (40) of the pump and not vice versa.

For illustrative purposes, the second non-return valve (6) comprises aspherical shutter (60) with a spring (61) to maintain the valve normallyclosed.

Referring to FIG. 2, an upper sheet (8) is formed of a strip made ofleather or imitation leather, with very low thickness and a basicallyrectangular shape with rounded corners, with higher dimension than thefoot. A plurality of transpiration holes (80) is obtained in the frontand central part of the upper sheet (8). Instead a plurality of holes(81) for fixing to the mold is obtained in a peripheral part of theupper sheet (8), as illustrated below.

Referring to FIG. 3, the upper sheet (8) is disposed above the lowersheet (3), the connection pipe (20), the valve unit (7) and the pump(4). The upper sheet (8) is coupled to the lower sheet (3) and to thepump (4) by means of stitching (82) or gluing, along a peripheral partof lower sheet (3) and pump (4). The function of the leather upper sheet(8) is to maintain the entire ventilation system (2) together duringmolding.

In this way, between the lower sheet (3) and the upper sheet (8) awrapping is generated, defining a chamber (35) (FIG. 4) formed of airspaces (32) for the passage of air. The holes (80) of the upper sheetcommunicate with the chamber (35) and the air spaces (32) of the lowersheet. Therefore the air above the upper sheet (8) is extracted by thepump (4) and ejected outside the shoe through the outlet pipe (21).

Referring to FIG. 5, the ventilation system (2) is inserted in a mold(100) for injection molding of polyurethane foam. The mold (100)comprises a die (101) and a lid (102).

The die (101) is provided with a back longitudinal hole (103) from whichthe outlet pipe (21) comes out to be connected to an external pump (P).

The mold (100) is closed with the lid (102) that is uniformly disposedabove the upper sheet (8) closing the holes (80). The lid (102) isprovided with vertical pins (104) that protrude downwards. Referring toFIG. 5A, the pins (104) of the lid cross the peripheral holes (81) ofthe upper sheet and are engaged in suitable seats (105) of the die,firmly holding the upper sheet.

Between the die (101) and the ventilation system (2) a peripheral airspace is generated, surrounding the perimeter peripheral border of theventilation system.

The die (101) is provided with a plurality of vertical pins (106) thatprotrude upwards, which exert pressure on the lower semibody (41) of thepump, which is suitably made of rigid plastic material.

Pressurized air is injected by means of the external pump (P), flowingin the ventilation system (2) in such a way to generate a pressure ofabout 2 atmospheres inside the chamber (40) of the pump. In such a case,the non-return valves (5, 6) are adjusted in such a way to be one-wayonly in case of low pressure values. The high pressure of the air sentby the external pump allows to force the valve (5, 6) with reverse flowand put the chamber of the pump in pressure.

The pins (106) hold the ventilation system (2) against the lid (102) insuch a way that polyurethane does not enter between the upper sheet (8)and the upper part of the pump (4) during injection or casting. To thatend and for higher safety, air is injected inside the pump (4) so thatthe upper semibody (42) of the pump pushes the upper sheet (8) thatperfectly adheres to the lid (102).

Now, polyurethane foam can be injected in the mold (100), which isdisposed under the ventilation system (2), forming a lower layer (9) ofpolyurethane foam. The polyurethane foam (9) flows in the peripheral airspace, under the upper sheet (8), surrounding the perimeter peripheralborder of the ventilation system (2). In this way the polyurethane foamalso surrounds the peripheral borders of the ventilation system (2).

The ventilation system (2) has been specifically studied to allow forinjection molding of polyurethane foam. In particular, the injectionmolding of polyurethane has been possible because of the materials usedfor the pump (4) and because of the fact that the chamber (40) of thepump is maintained under pressure during molding.

The injection of polyurethane foam (9) allows for perfect couplingbetween the lower sheet (3) and the upper sheet (8); between the twosemibodies (41, 42) of the pump; between the valve unit (7) and the pump(4); and between the pump (4) and the upper sheet (8).

As shown in FIG. 6, a semi-finished insole (S) is obtained from the mold(100), wherein the lower layer (9) of polyurethane foam has perimeterborders (90) that surround the peripheral border of the ventilationsystem (2) under the upper sheet (8).

The upper sheet (8) has a peripheral portion (84) that protrudesexternally with respect to the borders (90) of the polyurethane layer.Accordingly, the upper sheet (8) is cut with shearing process along acutting line (83) in correspondence with the perimeter border (90) ofthe polyurethane layer. In such a way, as shown in FIG. 7, a finishedinsole (S) is obtained, which is compact, stable and comfortable.

FIG. 8 shows a shoe with upper (T) and bottom (1) joined to the upper(T). An outsole (11) is fixed under the bottom (1).

The insole (S) comprising the ventilation system (2) is disposed on thebottom (1). A hole (10) is made in the heel area between bottom (1) andupper (T) to pass the air outlet pipe (21) in such a way that air isejected out of the shoe. If necessary, in the heel area of the shoe, aquarter stiffener (15) is disposed between outsole (11) and upper (T),which is provided with a channel (16) in communication with the hole(10) to guide the ejection of the air out of the shoe.

The insole (S) can be of removable type or can be glued to the bottom(1).

When walking, the user presses the pump (4) with the heel. Consequently,the air is extracted through the holes (80) of the leather strip andejected from the chamber (40) of the pump outwards, ensuring ventilationinside the shoe.

It must be noted that the ventilation system (2) of the invention doesnot modify or interfere with the structure of the bottom (1) or outsole(11) of the shoe. Therefore, in case of accident-prevention shoes, metalplates or Kevlar sheets can be disposed in the outsole (11) or in thebottom (1) without interfering with the ventilation system.

Numerous variations and modifications can be made to the presentembodiment of the invention by an expert of the art, while still fallingwithin the scope of the invention as claimed in the enclosed claims.

1. A method of producing an insole for a shoe comprising a ventilationsystem, the method comprising: placement of said ventilation systeminside a mold for injection molding of polyurethane foam, in such a wayto form a lower layer of polyurethane foam disposed under theventilation system with borders folded in such a way to surround theperipheral borders of said ventilation system.
 2. The method as claimedin claim 1, wherein said ventilation system is obtained: connection to apump of a lower sheet, by means of a connection pipe, said lower sheethaving the shape of the front of a foot and being provided withdeformable spacers that protrude upward, connection to said pump of anair outlet pipe, and; application of an upper sheet on said pump andsaid lower sheet in order to form a wrapping between lower sheet andupper sheet generating a chamber, said upper sheet being provided withholes in communication with said chamber of the wrapping.
 3. The methodas claimed in claim 2, wherein said pump is obtained by coupling a rigidlower semibody and a deformable upper semibody to form a pumping chamberand during the injection of polyurethane foam, the chamber of the pumpis maintained at a pressure of approximately two atmospheres.
 4. Themethod as claimed in claim 2, wherein said upper sheet is made ofleather or imitation leather and is sewn to a peripheral part of saidlower sheet and said pump.
 5. The method as claimed in claim 2, whereinduring the molding process the upper sheet is fitted to a lid of themold by pins of the lid and said pump is pushed by pins of a die of themold.
 6. An insole obtained by the method claimed in claim 1, whereinsaid insole comprises a lower layer of polyurethane foam obtained byinjection molding, disposed under a ventilation system with bordersfolded in such a way to surround the peripheral borders of saidventilation system.
 7. The insole as claimed in claim 5, wherein saidventilation system comprises: a pump that forms an air chamber disposedin the user's heel area; a lower sheet provided with a plurality ofdeformable spacers that protrude upward and disposed in correspondencewith the front part of the foot; an upper sheet disposed on the pump andon the lower sheet in order to form a wrapping between lower sheet andupper sheet generating a chamber, said upper sheet being provided withholes in communication with said chamber of the wrapping to extract airfrom inside the shoe; a connection pipe connecting the chamber of thewrapping to the chamber of the pump, and; an air outlet conduitconnecting the chamber of the pump with the outside of the shoe for airejection.
 8. The insole as claimed in claim 7, wherein said upper sheetis made of leather or imitation leather, is shaped as a foot and isdisposed above the folded borders of the lower layer of polyurethanefoam.
 9. The insole as claimed in claim 7, wherein said pump comprises:a lower semibody made of hard thermoplastic polyurethane (TPU) withShore A hardness higher than 95 and an upper semibody made of softthermoplastic polyurethane (TPU) with Shore A hardness lower than 65.10. The insole as claimed in claim 7, wherein said ventilation systemfurther comprises: a first non-return valve disposed between said pumpand said air outlet conduit to permit air flow from the chamber of thepump to the air outlet conduit and not in the reverse direction, and; asecond non-return valve disposed between said pump and said connectionconduit to permit air flow from the connection conduit towards towardthe chamber of the pump and not in the reverse direction.
 11. The insoleas claimed in claim 10, wherein said first and second non-return valvesare disposed inside corresponding channels of a valve unit formed of arectangular block disposed in the front part of said pump.
 12. A shoecomprising: an upper, and; a bottom fixed to the upper, wherein the shoecomprises an insole as claimed in claim
 5. 13. The shoe as claimed inclaim 12, wherein the shoe is an accident-prevention shoe, comprising ametal plate or Kevlar sheet disposed in the bottom or in an outsoleapplied under the bottom.